LDRD Seminar Series: ‘Proteolytic Enzymes from Ocean Sediments Archaea’
Protein Crystallographer Karolina Michalska (BIO) will discuss her Laboratory-Directed Research and Development (LDRD) sponsored work at the LDRD Seminar Series presentation Tuesday, Aug. 29, 2017.
“Proteolytic Enzymes from Ocean Sediments Archaea” begins at 12:30 p.m. in the Bldg. 203 Auditorium. All are welcome to attend.
The ocean plays a critical role in the earth’s carbon cycle, with deep-sea sediments acting as the ultimate sink for organic carbon, storing approximately 40 percent of it. At the same time, this cold environment represents one of the richest microbial niches, constituting about one tenth of the total planet biomass. However, the vast majority of these microorganisms have never been grown and characterized in the laboratory, and therefore they been referred to as Microbial Dark Matter (MDM).
These diverse, heterotrophic and widespread microorganisms control carbon flow through organic matter decomposition, yet their impact on ecosystems and major global elemental cycles remains unknown. Nevertheless, sequencing of individual genomes and metagenomes from MDM projects has the potential to reveal novel functionalities and unexpected properties. Recently, single-cell genomics uncovered a number of new key players involved in deep-sea biogeochemistry, such as the miscellaneous crenarchaeotal group and the marine benthic group-D belonging to the kingdom of Archaea. Each of these uncultured microorganisms harbors predicted enzymes that have never been studied. In particular, these widespread archaea encode putative intra- and extra-cellular protein-degrading enzymes (proteases) very likely produced to utilize detrital proteins deposited in sediments as a source of basic nutrients. Consequently, they can contribute to carbon and nitrogen cycling.
The purpose of this project is to produce these uncharacterized proteins in the laboratory and investigate their biochemical and structural properties to understand how marine microorganisms contribute to biogeochemical processes via protein remineralization in sediments. The ability to perform detailed characterizations of enzymes from native subsurface microorganisms, without requiring that those organisms first be grown in pure culture, holds great promise for understanding key carbon transformations in the environment. Some of these new enzymes may yield biomedical and biotechnological applications.
Karolina Michalska joined Argonne in 2010. Her major interest is structural biology with a focus on protein structure — function relationships in biochemical transformations, primarily in prokaryotes. She has been contributing to two NIH-funded programs: The Midwest Center for Structural Genomics and The Center for Structural Genomics of Infectious Diseases. Recently, Michalska has been focused on structural basis of contact-dependent growth inhibition (CDI) systems — a means of bacterial competition in microbial communities, and evolution and functionality of essential enzymes involved in tryptophan biosynthesis in bacteria. As a member of The Structural Biology Center, she has also studied proteins involved in degradation of abundant biopolymers: cellulose, lignin, chitin and proteins. She has also contributed to the SBC R&D projects.
Michalska is a protein crystallographer in the Biosciences Division and a fellow at the University of Chicago Computation Institute. Prior to joining Argonne, she worked at Adam Mickiewicz University, Poznan, Poland, where she received her Ph.D. in chemistry.